US2392592A

US2392592A - Process of manufacturing built-up permanent magnets

Info

Publication number: US2392592A
Application number: US369882A
Authority: US
Inventors: Iseki Takeshi
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-12-29
Filing date: 1940-12-12
Publication date: 1946-01-08
Anticipated expiration: 1963-01-08

Description

Jan. 8, 19 46. 115m 2,392,592

PROCESS OF MANUFACTURING BUILT-UP PERMANENT MAGNETS Filed Dec. 12, 1940 Patented Jan. 8, 1946 PROCESS OF MANUFACTURING BUILT-UP PERMANENT MAGNETS Takeshi Iseki, Toyonaka, Japan; vested in the Alien Property Custodian Application December 12, 1940, Serial No. 369,882

In Japan December 29, 1939 2 Claims.

, This invention relates to improvements in the process of manufacturing a built-uppermanent ma net which consists of a piece of magnet and two pieces of soft iron attached to said magnet with one end of each soft iron piece acting as the magnetic pole, and more particularly to the method of building up a permanent magnet, wherein a magnet piece and two soft iron pieces are put together by an intervention of thin nonmagnetic metallic plates which are attached to both sides of the magnet and soft iron pieces by electrical spot-welding method, and the tight and close contact of the magnet and soft iron pieces is made by the contraction of the heat-expanded metallic plates.

Hitherto, the elements of the built-up permanent magnet has been put together by means of screws, solder or riveting, but these methods involve such diiilculties as drilling and tapping in the soft iron and non-magnetic metallic plates leaving unavoidable and allowable clearance between the contacting surfaces of the magnet and soft iron pieces, thereby causing a considerable magnetic loss. Moreover, these processes are expensive and clumsy because it is not an easy task to get a proper fit of the magnet into the space formed bythe soft iron pieces and the covering metallic p tes.

The present invention successfully does away with these difficulties. and perfect contact between the magnet and soft iron pieces can be readily and economically attained.

Fig. l is a side elevation showing one form of a built-up permanent magnet according to the present invention;

Fi 2 is a sectional view taken on the line 11-11 of Fig. 1;

F18. 3 is a side elevation of another form of the invention showing in addition, means for holdin the parts of the magnet in position for permanent attachment to one another, and

Fig. 4 is a sectional view, partly in elevation, taken on the line IV-IV of Fig. 3.

As shown in Figs. 1 and 2 a built-up permanent magnet made according to the present invention, wherein two soft iron pieces B with one end of each as the pole are put together with the permanent magnet piece A by an intervention of two pieces of thin non-magnetic metallic plates C placed so as to cover both sides of the ma net and the soft iron pieces.

To build up the permanent magnet according to this invention, the magnet piece A and the soft iron pieces'B are tightly put together in facial contact, and non-magnetic metallic plates C are placed on both sides of the magnet and the soft iron pieces so as to bridge them over. Then the non-magnetic plates alone are heated for a few seconds, and the prearranged elements are electrically spot-welded at the points indicated in the drawing by small dotted circles D. When the non-magnetic metallic plates are cooled, the magnet and the soft iron pieces come to very tight and close contact with eachv other due to the contraction of the metallic plates. It is necessary that the contacting surfaces of the magnet and the soft iron pieces previously be finally finished to insure close contact. I

In the example of Figs. 3 and 4 soft iron pieces B are placed on both ends of the permanent magnet A so that the permanent magnet is held between the soft iron pieces.

E is a frame of the device made of a metallic circular ring. G are set screws radially provided on the frame of the device the inner ends of the screws being extended into the inside of the frame.

A spring arm H is pivoted on each surface of the frame. This spring arm can be swung by means of a knob I, and when it is swung outwardly its free end rides on the surface of the frame.

To practise this invention, the elements, that is, permanent magnet A, soft iron pieces B and covering plates C are inserted in the frame of the device as illustrated in the Figures 3 and 4, and the permanent magnet and the soft iron pieces are put together tightly by means of the set screws and the non-magnetic metallic plates C are properly held on the surface of the magnet and soft iron pieces in such a way as to bridge over the contacting lines of the pieces by means of the spring arm H.

When the necessary prearrangements are completed, one end of the covering plates on both sides is spot-welded to one of the soft iron pieces at the points marked D. Then the covering plates are heated by'a gas burner, for e ample, for a few seconds, and the other end of the covering plates while still hot are spot-welded to the other soft iron piece at the points marked D.

In the illustrated instance in Figs. 3 and 4 the magnet A and the non-magnetic metallic plates C are not welded together, because the soft iron pieces hold the magnet so tightly due to the contraction of the plates that the welding becomes unnecessary, but the direct welding to the magnet may be used wherever such method is deemed desirable, depending upon the sizes and shapes of the built-up magnet.

.Ihe built-up permanent magnet manufactured by this new process contains no screws, neither is it riveted nor soldered. This is anew product as a built-up permanent maanet' per se.

What I claim is: a I

1. A manutacturinz process of a built-u permanent maanet wherein a sort iron piece is attached in facial contact to opposite poles or a permanent magnet piece, and non-magnetic plates are placed to cover opposite sides of said permanent magnet and soft iron pieces, and said plates are spot welded to one o! the pieces at one side or a racial contact and heated and while hot, welded to another c5 said pieces at the opposite of said facial contact so that tlaht facial conattalned by the contraction of the metal AA in s lat-se a,sos,sos

2. A manufacturing process oi a permanent ma net wherein two soit iron pieces are attached in facial contact to a permanent magnet piece at opposite poles, the faces of contact beinl approximately parallel. non-nuanetic plates are placed on opposite sides of said permanent magnet and soft iron pieces and said plates are spot welded to one of said soft iron Pieces and heated and while hot, spot welded tothe other of said soft iron pieces so that the permanent maa'net piece is firmly held between the soft iron pieces on contraction of the metal plates.

TAKESHI ISEKI.